Foldable crates are widely used these days. There are numerous solutions known in the art for locking mechanisms for foldable crates. The general concept of such locking mechanisms is that a foldable crate can be secured in open conformation, by a locking mechanism, which is releasable by an actuator, typically a tab surrounding the handle of the crate. It is believed that the pertinent state-of-the-art is represented by: U.S. Pat. No. 7,861,878, U.S. Pat. No. 6,290,081, US20100230406, US20120091133 and US20100320202; EP2431283 and EP1655232, as well as by WO2010146190, WO2009100799 and particularly DE10137328.
US20120091133 discloses a collapsible box including a plastic structure with a rectangular base, two ends, and two sides which are pivotably coupled to the base. The ends include centered parts combined with latches, which in one position anchor the sides and ends, while in another position the connection between the ends and the sides is released in order to collapse the elements. The collapsible box of US20120091133 is characterized in that the box includes an anchor device consisting of a series of rotary bodies that connect the latches to the centered part via two pairs of resilient parts and which, in the inoperative position thereof, hold the latches outwards, attaching the ends and the sides. When the central part is moved upward, the latches thus release the ends and the sides.
U.S. Pat. No. 7,861,878 discloses a fastening device for folding boxes. The folding boxes include a bottom and four lateral walls coupled in jointed fashion to the edges of that bottom, two opposite walls each having a fastening device for ensuring the unfolding of the box. The fastening devices of U.S. Pat. No. 7,861,878 include a vertically displaceable central piece and lateral bolts with horizontal displacement for fastening the lateral walls via their adjacent edges. The fastening device of U.S. Pat. No. 7,861,878 includes elastic spring elements that link the central control piece with pairs of the lateral bolts. The spring elements, in the rest position, maintain the bolts in an engagement and fastening position. The release position of the bolts in U.S. Pat. No. 7,861,878 results when the spring elements pull the bolts against the resistance of the elastic elements.
DE10137328 that is considered the most relevant prior art publication discloses an assembly, adapted to open and close side walls of a plastic and reusable box or container, which have a manual locking unit, with at least one projection, which grips over a ratchet hook on the longitudinal wall. The lock operating control is adapted to grip, carry the box or container and also unlock the side walls.